1. Field of the Invention
The present invention relates to a process and method for the transmission of encrypted information between a normally mobile or handheld reporting device and a central controller, whereby the information encryption as well as the transmission is dependent on the voice characteristics of a spoken password.
2. Description of the Prior Art
On the current battlefield, information between a central control post and one or more reporting devices is transmitted via radio or cable in digitally encoded form (with or without encryption) or with voice information. The voice, whether digitally encoded or as analog signals, is immediatly recognized as a known comrade. The non-encrypted digital data is accepted without automatically checking the authorization or identification-authentication. Encrypted messages are likewise accepted without authorization or authentication checks. Encryption keys are sent via physical means; i.e. they are collected or delivered in the form of a card or as printed information. The information is multifariously transmitted per radio transmission. Thereby, the receiving operator cannot recognize the operator of the transmitter.
Basically, the following problems exist:
1. Reporting devices, for example those of the forward observation units, could be captured. Listening into the transmissions and the sending of false messages follow after such capture. The loss of the transmission post and the device is either not discovered or is recognized too late.
2. If the message between the command post and a forward observer is transmitted encrypted, then there exists the danger that the enemy will get control of the key, either through trickery or force. The key must be changed often. According to the usual process, a safe, independent channel is necessary to transfer the key. In any case, it is impossible to establish whether the device including its operator have been captured or whether the device alone has been captured. The voice messages can be deceptively sent by threatening the operator; digital messages could be accepted for some time without doubt, especially in the case of encryption, whereby the messages from the transmitting post are considered especially safe. From time to time, the key must be changed; the more frequently the better.
Partial aspects of the above described problems are solved in the field via voice transmission, digitalyzing the messages and encrypting of the messages, and the problems mitigated by means of procedures and devices. Procedures for encrypted information transmission are known; e.g. DE 1 062 750 (German Patent) describes such a procedure. The disadvantage of this procedure is that the recognition of the operator is not possible. Further, a speech recognition procedure is known from the European Patent 0 027 596 A1, by which the voice of the operator is recognized by comparison of his voice characteristics stored in a memory. The disadvantage of said described procedure is due to the fact that an unauthorized person can change the voice characteristics stored in the device and can therefore send false messages and can receive encrypted messages; this would be either recognized too late or not at all.